All manner and variety of absorbent articles configured for the absorption of bodily fluids are, of course, well known. Current types of absorbent articles include sanitary napkins, pantiliners, disposable diapers, and incontinent articles.
One material which has been widely utilized as a topsheet material in absorbent articles is disclosed in commonly assigned U.S. Pat. No. 4,342,314 issued to Radel, et al. on Aug. 3, 1982 and hereby incorporated herein by reference. Radel, et al. discloses an absorbent bandage with a wearer-contacting topsheet comprising a resilient, macroscopically expanded, three-dimensional plastic web exhibiting a combination of fiber-like and plastic properties. In a preferred embodiment, the macroscopically expanded, three-dimensional, plastic web topsheet disclosed in Radel, et al. exhibits a fine scale three-dimensional microstructure comprising a regulated continuum of capillary networks originating in and extending from one surface of the web and terminating in the form of apertures in the opposite surface thereof to promote rapid fluid transport. The web's fiber-like appearance is comprised of a continuum of fiber-like elements, the opposed ends of each of the fiber-like elements are interconnected to at least one other of the fiber-like elements.
A typical capillary network in the Radel, et al. structure comprises an uppermost capillary opening or aperture formed by a multiplicity of fiber-like elements interconnected to one another in the uppermost plane of the web. Each of the fiber-like elements exhibits a substantially uniform U-shaped cross-section along its length. The cross-section of the fiber-like element comprises a base portion located in the wearer-contacting plane and a sidewall portion joined to each edge of the base portion, the sidewall portions extend generally in the direction of the absorbent pad-contacting surface of the web. The sidewall portions which intersect one another are joined to one another intermediate the wearing contacting surface and the absorbent pad contacting surface of the web, thereby forming a capillary network interconnecting the opposed surfaces of the web.
A topsheet of the type generally disclosed by Radel, et al. is highly effective in promoting rapid fluid transfer from the first, wearer-contacting surface to the second, absorbent pad-contacting surface of the topsheet. Accordingly, topsheets of this type have enjoyed widespread commercial success on catamenial pads due to their clean and dry appearance in use when contrasted to conventional nonwoven fibrous topsheets or two-dimensional films. While an absorbent article having a topsheet of the type disclosed in Radel, et al. is highly effective in promoting rapid transfer of bodily fluids from the first, wearer-contacting surface to the second, absorbent pad-contacting surface, the degree of masking of bodily fluids, e.g., menses, retained within the absorbent core is dependent upon the size of the capillary networks. As the size of the capillary networks decreases the amount of masking provided by the topsheet increases. However, if the capillary networks are too small bodily fluids are not able to pass through the topsheet into the absorbent core thereby exposing the skin to moisture.
Conventional nonwoven topsheets have been found to provide desirable visual and tactile properties from the wearer's perspective, as well as good flexibility and softness properties. However, the fluid-handling performance of conventional nonwoven topsheets has been found to be less than optimal, particularly with comparatively more viscous bodily fluids, contributing to a "wet" tactile impression after exposure to bodily fluids. In addition, residual fluid typically remaining within the nonwoven material itself after use creates a less-than-desirable visual impression.
With either conventional formed film topsheets or conventional nonwoven topsheets, one proposed solution to enhance the masking performance of such topsheets with regard to fluid within the absorbent article has been to employ opacifiers in the materials of the topsheet itself. For example, formed film topsheets and nonwoven topsheet materials have been developed which utilize whitening and/or opacifying agents such as titanium dioxide within the materials themselves. While such materials exhibit improved masking of underlying fluids below the topsheet, their light and often white coloration increases the visual contrast with residual bodily fluids remaining upon the surface after use, negating any improvement in masking of underlying fluids.
Accordingly, it would be desirable to provide a fluid previous web suitable for use as a topsheet in an absorbent article which provides the fluid handling capabilities of a formed film material and the softness of a nonwoven material.
It would also be desirable to provide a topsheet material having desirable visual and tactile properties, including masking and soft tactile impression, while providing good fluid handling performance.